1  #---
   2  # Excerpted from "Agile Web Development with Rails, 3rd Ed.",
   3  # published by The Pragmatic Bookshelf.
   4  # Copyrights apply to this code. It may not be used to create training material, 
   5  # courses, books, articles, and the like. Contact us if you are in doubt.
   6  # We make no guarantees that this code is fit for any purpose. 
   7  # Visit http://www.pragmaticprogrammer.com/titles/rails3 for more book information.
   8  #---
   9 
  10 
  11  class Product < ActiveRecord::Base
  12    has_many :orders, :through => :line_items
  13    has_many :line_items
  14    # ...
  15 
  16 
  17    def self.find_products_for_sale
  18      find(:all, :order => "title")
  19    end
  20 
  21    # validation stuff...
  22 
  23 
  24 
  25 
  26 
  27    validates_presence_of :title, :description, :image_url
  28 
  29 
  30    validates_numericality_of :price
  31 
  32 
  33    validate :price_must_be_at_least_a_cent
  34 
  35 
  36    validates_uniqueness_of :title
  37 
  38 
  39    validates_format_of :image_url,
  40                        :with    => %r{\.(gif|jpg|png)$}i,
  41                        :message => 'must be a URL for GIF, JPG ' +
  42                                    'or PNG image.'
  43 
  44 
  45 
  46  protected
  47    def price_must_be_at_least_a_cent
  48      errors.add(:price, 'should be at least 0.01') if price.nil? ||
  49                         price < 0.01
  50    end
  51 
  52 
  53 
  54  end